Attempts have been made to realize a wider viewing angle in liquid crystal display elements by using, as a retardation film, a stretched cellulose acylate film in which in-plane retardation (Re) and across-the-thickness retardation (Rth) have been developed by stretching.
Examples of a process for producing such a cellulose acylate film may include a process in which a film is stretched in the longitudinal direction (longitudinal stretching), a process in which film is stretched in the transverse direction (transverse stretching), and a process in which film is stretched simultaneously in the longitudinal and transverse direction (simultaneous stretching). Among these processes, the longitudinal stretching has hitherto been used in many cases (see, for example, Japanese Patent Laid-Open No. 2002-311240).